In general, a refrigerator is an apparatus for freshly storing foods at a low temperature for an extended period of time, by maintaining a low temperature in a freezing chamber and a refrigerating chamber by using cool air. With the development of the industrial society, the refrigerators have been used in each house by enormous demand and supply.
The refrigerator has a freezing cycle including, as basic components, a compressor for compressing refrigerants into high temperature high pressure gas refrigerant, a condenser for condensing the refrigerant from the compressor into high temperature high pressure liquid refrigerant, an expansion valve for decompressing the refrigerant from the condenser into low temperature low pressure liquid refrigerant, and an evaporator for evaporating the refrigerant from the expansion valve into low temperature low pressure gas refrigerant, absorbing heat from the freezing chamber or the refrigerating chamber, and maintaining a low temperature in the freezing chamber or the refrigerating chamber.
On the other hand, people intend to make the indoor air fresh with the growing interest in health. However, in order to improve utilization of a restricted residential space, a kitchen and a living room are opened as the dining-living area, and electric home appliances including the refrigerator are mostly installed in the dining-living area. Accordingly, gas is possibly leaked from a gas range in the kitchen, dusts flow in the living room through a veranda or window, and moisture causing errors of the electric home appliances increase by various factors.
Recently, the refrigerator installed at the center of the residential space is required to have a function of deciding contamination of the indoor air and providing contamination solving methods.